As the stem cells that can be differentiated into various tissue cells, embryonic stem cells (ES cells), which are the cells derived from the undifferentiated zygote, somatic stem cells, which are undifferentiated cells that are contained in differentiated tissues, and the like are known.
Somatic stem cells are present in a variety of tissues in the body, and examples thereof include mesenchymal stem cells present in the bone marrow.
Mesenchymal stem cells are undifferentiated cells that can be differentiated into cells belonging to mesenchymal tissues such as bone, muscle, and fat, and are known to be capable of differentiating also into ectodermal cells such as nerve cells and endodermal cells such as liver cells.
Also, mesenchymal stem cells have drawn attention for their ability to restore the function of a dysfunctional tissue by differentiating into the cells in such a tissue. Specifically, for example, bone marrow-derived mesenchymal stem cells have drawn attention for their potential to differentiate into the cells in inflamed tissues or damaged tissues under the influence of differentiation inducers, which induce differentiation, by being attracted to and accumulating in such tissues via the blood stream.
Meanwhile, conventionally, various substances are known as differentiation inducers that can differentiate mesenchymal stem cells into a variety of tissue cells. For example, substances containing PDGF-BB as the platelet-derived growth factor that can differentiate mesenchymal stem cells into muscle tissue cells are known (Patent Document 1).